The present invention generally relates to rotary recording mediums and reproducing apparatuses therefor, and more particularly to a rotary recording medium which is recorded with information signals related to different programs on different track turns on one recording surface thereof, and a reproducing apparatus for reproducing an information signal related to one selected and continuous program from such a rotary recording medium.
A new information signal recording and/or reproducing system has been proposed in U.S. Pat. Nos. 4,315,283 and 4,322,836, of which the assignee is the same as that of the present application. According to this proposed system, the recording system forms pits in accordance with an information signal being recorded along a spiral track on a flat rotary recording medium (hereinafter simply referred to as a disc), without forming a groove therein. In the reproducing system, a reproducing stylus traces over along this track to reproduce the recorded information signal in response to variations in electrostatic capacitance.
In this system, since no guide grooves for guiding the reproducing stylus are provided on the disc, it becomes necessary to record pilot or reference signals on or in the vicinity of a track of a program information signal, on the disc. Upon reproduction, the reference signals are reproduced together with the program information signal. Tracking control is carried out so that the reproducing stylus accurately traces along the track in response to the reproduced reference signals.
By use of this previously proposed system, there is no possibility whatsoever of the reproducing stylus or the disc being damaged since the recording track has no groove. The reproducing stylus can trace the same portion of the track repeatedly many times, whereby a special reproduction such as still picture reproduction, slow-motion reproduction, or quick-motion reproduction becomes possible in a case where the recorded information signal is a video signal.
In order to carry out the above special reproduction, a kick pulse is produced by a special reproduction mode control circuit, and this kick pulse is applied to a tracking control coil in a signal pickup reproducing device, to shift the reproducing stylus to an adjacent track. Because the track is formed in a spiral manner, upon still picture reproduction, for example, the reproducing stylus is shifted to an adjacent track in the outer peripheral direction of the disc, once for every revolution of the disc. During slow-motion reproduction, the reproducing stylus is shifted to an adjacent track in the outer peripheral direction of the disc, once for every predetermined number of revolutions over one inclusive of the disc. Further, upon quick-motion reproduction, the reproducing stylus is shifted to a track in the inner peripheral direction of the disc.
Accordingly, the above conventional special reproduction was performed by carrying out still picture reproduction, slow-motion reproduction, and quick-motion reproduction with respect to a part of a program continuously recorded on the tracks formed on the disc.
However, there is now a demand for recording and reproducing various information programs on the disc. Hence, it is highly desirable to realize a new special reproducing system for obtaining a special reproduction picture such as a reproduction picture obtained by composing different recorded information and a reproduction picture obtained by selecting information from among a plurality of recorded information.
Hence, the present inventor has endeavored at realizing a new disc which satisfies the above demands. That is, he has endeavored to realize a disc recorded with a kick signal at predetermined positions for shifting the reproducing element to an adjacent track, so as to suitably select different plurality of program video information recorded on each track according to the kick signal obtained during reproduction to obtain a reproduced picture. Hcwever, in this disc, the kick signal must be recorded at predetermined positions on the disc. Thus, the circuit construction of the recording system became complex. In addition, a circuit for discriminating and reproducing the recorded kick signal became necessary in the reproducing system. Accordingly, there was a disadvantage in that the circuit construction became complex in the recording and/or reproducing apparatus.
Further, it was found that if the audio signal is recorded in a normal manner, there is a problem in that discontinuity is introduced in the reproduced audio information when the program of the above program video information is selectively reproduced. That is, if the reproducing element is shifted within a vertical blanking period of the video signal recorded on the track, no inconvenient phenomenons appear in the reproduced picture obtained by the reproduced video signal due to the above shift. However, discontinuity is introduced in the audio signal.